Hayabusa - Reentry and Capsule Retrieval

Reentry and Capsule Retrieval

The reentry capsule and the spacecraft reentered to the Earth atmosphere on 13 June 2010 at 13:51 UTC (23:21 local). The heat-shielded capsule made a parachute landing in the South Australian outback while the spacecraft broke up and incinerated in a large fireball.

An international team of scientists observed the 12.2 km/s entry of the capsule from 11.9 km (39,000 ft) on board NASA's DC-8 airborne laboratory, using a wide array of imaging and spectrographic cameras to measure the physical conditions during atmospheric reentry in a mission led by NASA's Ames Research Center, with Peter Jenniskens of the SETI Institute as the project scientist.

Since the reaction control system no longer functioned, the 510 kilograms (1,100 lb) space probe re-entered the Earth's atmosphere similar to the approach of an asteroid along with the sample re-entry capsule, and, as mission scientists expected, the majority of the spacecraft disintegrated upon entry.

The return capsule was predicted to land in a 20 km by 200 km area in the Woomera Prohibited Area, South Australia. Four ground teams surrounded this area and located the re-entry capsule by optical observation and a radio beacon. Then a team on board a helicopter was dispatched. They located the capsule and recorded its position with GPS. The capsule was successfully retrieved at 7:08 UTC (16:38 local) of 14 June 2010. The two parts of the heat shield, which were jettisoned during the descent, were also found.

After confirming that the explosive devices used for parachute deployment were safe the capsule was packed inside a double layer of plastic bags filled with pure nitrogen gas to reduce the risk of contamination. The soil at the landing site was also sampled for reference in case of contamination. Then the capsule was put inside a cargo container which had air suspension to keep the capsule below 1.5 G shock during transportation. The capsule and its heat shield parts were transported to Japan by a chartered plane and arrived at the curation facility at the JAXA/ISAS Sagamihara campus on June 18.

Before the capsule was extracted from the protecting plastic bag, it was inspected using X-ray CT to determine its condition. Then the sample canister was extracted from the reentry capsule. The surface of the canister was cleaned using pure nitrogen gas and carbon dioxide; it was then placed in the canister opening device. The internal pressure of the canister was determined by a slight deformation of the canister as the pressure of the environment nitrogen gas in the clean chamber was varied. The nitrogen gas pressure was then adjusted to match the internal canister pressure to prevent the escape of any gas from the sample upon the opening of the canister.

On October 7, 2010, it was announced that approximately 100 particles were collected by the sample canister, and stated that some may be cosmic materials. The particles are smaller than 0.001 millimeters. In November, JAXA performed detailed analyses of the samples by splitting each particle and examining their crystal structure at SPring-8.

A government adviser and former lieutenant general, Toshiyuki Shikata, stated that part of the rationale for the reentry and landing part of the mission was to demonstrate "that Japan's ballistic missile capability is credible."